Photographic objective



} SearhiRdgi A. w. TRONNIER PHOTOGRAPHIC OBJECTIVE Jan. 1a, 1938.

Filed Aug. 31, 1935 W 1w J *Wm OPTICS r rumreo STATES HP-H) Patented Jan. 18; ll

Search Room PATENT OFFICE PHOTOGRAPHIC OBJECTIVE Albrecht Wilhelm Tronnier,

Bad Kreuznach,

Germany, assignor to the Corporation of Jos. Schneider & 00., Optotec-hnische Gesellschaft,

Berlin, Germany Application August 31, 1935, Serial No. 38,816 In Germany January 15, 1935 1 Claim.

object side, while on the other side of this dispersive lens there is a cemented, meniscus-shaped collective component the collective cemented surface of which is concave toward the image side and the convex outer surface of which faces toward the image side. Such objective, with a relative opening of more than 1:35, permits attaining a good zone reductional correction within, as well as outside of, the axis over an image field of more than 50 to 60, without it being necessary to use extremely great surface curvatures or particularly long paths of glass to attain this high degree of efficiency.

The present invention permits of an appreciable increase in the constructional length of such objectives with such correction of aberrational errors that within the aforesaid image field the positional aberrations of the sagital and meridional image surfaces may be kept below about of the focal length, with such corrections of the spherical aberrations that their greatest zonal longitudinal error remains below about of the focal length. By fully retaining these error limits the constructional length of the objective can be kept less than of the focal length of the objective. This is accomplished by such distribution of the refractive efiect among the two collective lenses, which precede the individually spatially disposed dispersing lenses, whose total focal length is at least 40%, and at most 80%, of the focal'length of the entire objective, so that the rest effect consisting of the algebraic sum of the surface ffects (25 each individual one of which 39 is equal to the product of the auxiliary radiation incidence height (hi), the refractory difference (ni-n1) and radii reverse value (1: 11), whereby the surface index is then designated by i, directed toward the front .lens amounts to between 50 and 95% of the rest effect i'v directed toward the collective member following the front lens, and whereby further, the focal length of the first collective member is per se smaller than the focal length of the complete objective. The new objective is diagrammatically illus+ trated in the drawing, which shows a longitudinal section through an objective corresponding to the measurements of the following examples.

In the drawing the objective components as illustrated, may consist of a single collective lens I, a collective meniscus lens'II, an unsymmetrical double concave dispersive lens III and a meniscus shaped doublet IV. Reference characters di to d designate the central thickness of,

the lenses, A1, A2, and A3, the air gaps and Rl to R9 the radii.

This surface effect 7,) may be expressed as a formula thus:

Wherein nr-m designates the difference of the refraction exponents of the adjacent media of these involved surfaces, 111 designating the preceding and n'i the following medium. 11 is the length of the radius of the corresponding surface 2', while by the statement of the incidence height hi of the parallel vauxiliary ray on the corresponding i surface also clearly gives the position of this surface with respect to the preceding surfaces.

Since the rest effect on a certain surface 2' always is the sum of the preceding surface effects, it follows that:

wherein Z is the first surface of the system and k the surface to be regarded as straight, for ex- 4 VI: F V F F and V1I=W "4 2 The focal length of the numerical embodiment given is equal to unity. The distance of the Gauss image plane from the image vertex of the last lens is designated by p'e. The indicated refractive exponents correspond to the yellow ray whereas the color dispersion is designated by the Abbe letter v.

Relative aperture f2.9 Pe:.8186

d1=.05717 111:1.5890 v =61.2 R2=- 12.234 I Al=.00407 air R3=+ .5424

d2=.04070 n2=1.6375 v,=56.1 R4=+ .8521

A2=.04884 air R5=- .7238

d3=.01647 113:1.6045 v,==37.8 R6=+ .3293

A3=.081'78 air diaphragm space R7=- 2.0391

d5=.07442 115:1.6025 v =59.5 R9= ,3935

' From the embodiment given we have, according to the data given in the copending application: 1

Height of Surface eflecl v incidence 25,

L 1.00 00 00 +1.36 25 84 2' .950976 +.04 5783 .94 52 44 +1.11 08 .88 26 32 .66 03 20 5. .79 18 47 .66 12 96 6. .77 51 l.43 ll 93 7. .79 86 52 -'.20 15 09 8. .806836 +.181820 9, .8185 96 +1.25 32 41 Rest effect Rest effect Pr, WY,

1. :|:.00 00 +1.36 25 84 2. +1.36 25 84 +1.40 83 67 3. +1. 40 83 67 +2. 51 92 57 4. +2.51 92 57 +1.85 89 37 5. +1.85 89 37 +1.19 76 41 6. +1.19 76 41 .23 35 52 7. .23 35 52 .43 50 61 8. .43 50 61, .25 32 41 9. Surface .25 32 41 +1.00 ()0 Corresponding to the principles set forth in the copending application it follows from the embodiment given that the surface effect of the collective cemented surface in the positive outer member (1v) F =+.1a1a20, and the rest effect directed towards the last surface (R6) of the dispersing member (III) v =.233552, and

it is clear that .181820 is greater than .233552:4. The rest effect '11 directed towards the last surface (R4) of the inner collective member (11) v =1.858937, the surface effect of the inner radius (R5) of the dispersing member (III) facing both of these collective members is =--.661296, and finally the surface effect of the outer radius (R9) of the cemented collective lens (IV) facing the shorter radiation width is while 1.483307 lies between the values and 2.

Furthermore, according to the present invention the rest effect 'v; directed towards the last surface (R3) of the front lens (I) preceding the inner collective member (II) on the side of longer radiation width is 'v,=+1.4os367, the rest effect f v directed towards the last surface of the inner collective member (as previously recited) is =+1.858937, and, as claimed, 1.408367 is greater than 50 per cent of 1.858937.

I claim:

Photographic objective of four components in contact with the air, in which a. single, uncemented and asymmetrical bi-concave dispersive lens is disposed behind two separate collective components located on the object side, While on the other side of this dispersive lens there is a cemented meniscus-shaped collective component, the collective cemented surface of which is concave toward the image side, has said cemented component having a convex outer surface toward the image side and the total focal length of the dispersive component being between 40% and 80% of the focal distance of the entire objective, the refractive power of the two separate collective components being such that the rest effect (R toward the front components (I) consisting 

